1. Field of the Invention
The present invention relates to a circuit breaker, and more particularly to a circuit breaker which can interrupt an excessively high electrical current consumption.
2. Description of Related Art
A circuit breaker is provided in a distribution box to prevent a high electrical current consumption from causing an accident. The circuit breaker is composed of a shell, a first and a second conducting strip provided in the shell, and a bimetal strip securely mounted on an upper end of the first conducting strip. The bimetal strip, i.e., two metal flats which have different thermal expansion factors, can electrically connect to the second conducting strip.
When an electrical current is excessively high and generates dangerous heat, the bimetal strip becomes heated and distorts, whereby a tip of the bimetal strip separates from the second conducting strip. Hence, the electrical current circuit is interrupted to prevent the overload of the current consumption.
Whether the circuit breaker has an action function depends on the flexibility of the bimetal strip. The bimetal strip of a conventional circuit breaker is pressed by a button. If a distortion power of the bimetal strip caused by the heavy current consumption is bigger than a friction from the button, the bimetal strip can separate from the second conducting strip. If the friction from the button is too big for the bimetal strip to act quickly, a product may be damaged because of the heavy current not being timely interrupted.
With reference to FIG. 5, a conventional breaker has a shell (not numbered), a first conducting strip (60) and a second conducting strip (61) respectively provided in a lower end of the shell. A first terminal (62) is mounted on an upper tip of the second conducting strip (61) and the first conducting strip (60) is connected to a first tip of a horizontal bimetal strip (63). A second tip of the bimetal strip (63) is mounted with a second terminal (64) which detachably connects to the first terminal (62).
A button (70) is mounted on an upper end of the shell and a curved spring (71) is provided under the button (70). A finger (72), a lower end of which is connected to the second tip of the bimetal strip (63), is mounted under the curved spring (71). An angle (A) is formed between the curved spring (71) and the second tip of the bimetal strip (63).
With further reference to FIG. 6, when the button (70) is in the ‘current flow’ mode and the current consumption then becomes excessive, the second terminal (64) separates from the first terminal (62) thereby the finger (71) being counter clockwise rotated.
With reference to FIG. 7, when the pressure on the button (70) is released, the curved spring (71) compresses against the finger (72) to clockwise rotate so that the button (70) moves to the ‘current interruption’ mode.
However, disadvantages of the conventional circuit breaker are described as follows:
1. The finger (72) can not pivot smoothly corresponding to the bimetal strip (63) if the bimetal strip (63) does not have a smooth surface such that the button can not move to the ‘current interruption’ mode completely when the pressure is released.
2. The finger (72) is directly compressed against the bimetal strip (63) to enable the bimetal strip (63) to return to the ‘current interruption’ mode such that the finger (72) should incline substantially corresponding to the bimetal strip (63). Furthermore, the bimetal strip (63) should have a big stored power to enable the finger (71) to rotate thereby having a small practicability.
Therefore, the invention provides a circuit breaker to mitigate or obviate the aforementioned problems.